Alzheimer’s disease (AD) is a common neurodegenerative disorder and the leading cause of dementia worldwide, for which there is currently no effective treatment. The early detection and diagnosis of AD are clinically significant for improving prognosis. Studies have shown that amyloid PET and 18F-fluorodeoxyglucose ( 18F-FDG) PET imaging are useful for the early diagnosis of AD. This article provides a review of the research progress on brain glucose metabolism in different populations with positive amyloid β (Aβ) PET imaging and the relationship between the two.